Inhaled nitric oxide (INO) will be evaluated as a potential therapy for term and near-term infants with hypoxic respiratory failure including infants with primary persistent pulmonary hypertension of the newborn (PPHN), meconium aspiration, sepsis/pneumonia, respiratory distress syndrome, suspected pulmonary hypoplasia, and congenital diaphragmatic hernia (CDH). (This is a NICHD Neonatal Research Network Trial.)